The use of LEDs has dramatically increased in recent years, particularly for automotive uses, because of their long life and relatively low direct current power consumption. A prime example has been the use of LED lamps for the high mount taillight required on automobiles and light trucks. Design problems have occurred when using these lamps because of the mounting requirements and the esthetics being undermined by the visibility of the circuit board and various electrical connections.
Additionally, it has been difficult to achieve consistent mounting without damaging the LEDs themselves, and in mounting the required heat sinks, which often were trapped between the printed circuit board (PCB) and a carrier, reducing the heat sink access to air and adversely effecting their cooling function. Still other problems arose because of the tolerance build-up between PCBs, carriers and heat sinks, which tolerances added to the LED focal point positional tolerance making it more difficult to achieve the desire optical performance, particularly where additional optics, such as Fresnel lenses, were being used. If reflector cups were used with the LEDs it was possible for the PCB to come into contact with the metallized reflectors, posing a risk for short circuits and failure of the lamp assembly.